Antishrinking treatment of animal fibers



Patented ct. 14, 1947 )55 Kill' IZKLNU' Huur vl u AN'rrsnRj-mKiNGTREATMENT oFfANiMAJ- FIBERS 1- Francis Malcolinustevensqn and.]ohnIAonard` Raynes,y Ambergate, England, assignors" to'- Stevensons (Byers)Limitc'd,` Ainbexjgatc', Eng?" land, a British' companyf' `lloDr-awingApplication May :3, 1945, Serial No.-vv 591,852.. InGreat BritainJune15,1943

12 claims.

1l rIhis invention .relates-to a method oftreating fabrics` orothervtextile materials consisting Wholly or partlyvof Wool, to reducethe -natural tendency to shrink-Whenwashed invaqueous liquors.

Wool goods. are usually treated to render `them unshrinkablewith anacidiiied solution of ahypochloriteat a pH varying from 1 to5 accordingto the nature of theuacid, and the quantity employed. Under theseconditionsthe `yvool fibre has such a sbtrongraffinityfor thehalogen,-that complete exhaustion of` the A bath takes place `Within afewl minutes.- This procedure cannot he expected'togive uniformpenetration of `*the chlorinating agent, especially?v Where highlytwisted yarns or thick fabrics are yunder treatment, and it generallyresults inlthe surface bres being over treated, while those in theVcentre of the yarn criabricremaineappreciably unaiected. lli thehy-prochlorite solution is-.used at an alkaline pli-We nd that. the`rate of reactionrwith the wool is much slowenowingto the fact .that as.the pH rises above-'7, itsechlorinating properties :rapidly diminish,until at pH 8-it actshalmost exclusively asY an oxidising agent. Underthe latter icondition, however,i although the Wool still gradzually.absorbs and lreacts :with the halogen, no :appreciable degree ofnon-felting is produced. These facts are `,responsible for thegeneralview that Wool-cantonly be rendered unshrinkable by idirectchlorination or bromination, and thatthe :oxidising .propertiesof thehalogens Vare inlcidental, and should he eliminated as-aras possible.vAs will bev indicated later inthis specication Wehave found ritpossible-to obtain resistance, to shrinkage :bytheluse of halogencompounds acting under. oxidising conditions, 4and Joy this method toretainA the natural properties fof the animal bres Whilst givingimproved ap- ,ipearance and handle of the treated goods.`

It is an object of the -invention'to .provide an iimprovedrmethodWherebyfthe materials may be subjected to an even-treatment which is@,Sily 'controlled, andy thereby-renderedshrinkfresistant `Without y thefibre beingjiimpoverished land V-vvith- (cria-1123) v out substantialloss of protein-matter, 4sozlhat the desirable natural proper-ties ofthe wool,flsuch :as fullness I of handle,V resilience, y etc.,; arevretained and the lWeight loss` during the treatment isex- Atremely 10W.

Another object of the -inventiongis Vto-provide :a vtreatment whichgives f such uniform results lthatlevelling in subsequentdyeing'operationsis vifaclitateCL yOurprocessis`V applicable. toWoolmaterialsicon- 2m tainingcelllilosi'c libres, such as cotton orrayon, Since" the itineraire'- sub'stantiauy' unchanged b y thetreatment. n

It is known that-'cold'dilute aqueoussolutions of alkalinehypocli'ljorites, 'hypob'romite'sg and'also knitrogen-chloro compoundssuch' .as nitrogen tric-liloride," monochlraniine; s ojdium-petoluene vsuli'ilnoAnclil'oramide; sodium" ro{dichlorolienzene the action .of'chlorine or h'yp'ochloriteson solutions or suspensibnsfofammonia,"primary orv secto .enable the Lfabri'cs" to 'betermed'shrink-resistarit. iisd` ,dilute aqueons*V solutions of permanganate"compounds'areikrioyvn to 'react with "animal libres, producingVmodification of fmolec- .ularfstructura hutjonly Slightdecrease inshrinkingvproperties. y

'The term nitrogen chloro compounds used in e,this.speciiic'a'tion'isintended to cover only nitro "chloro compoundsin 'Which'the' chlorine'atom is directlyattached .to the" nitrogen atom and'wiierein tliefchlorine is available chlorine;

We' have found .that by combining the' oxidisingk actfionofl permaganatel'cofmpo'unds` with the action 4of onejor' nir'e of" the .halogenYvcontaining compounds*mentioned alooveg'either in one bath orlinkseparate baths,"'subject' to the precautions ygiveri below'andunderfjsuitable')conditions as to pHy of' the solutions, "theanti-shrinking eiiect on U the animal bre is greatly enhancedjand We are,thusable' .to Lacliie'v'e "suclieffect' while still re- 'Utainingall",tl*i attractive ',"properties' fof Woollen nfabrics or 'ya ev'en'"g g Vwith low quality .ivoo'lsanl improved"y appearance, handlel and14,0 j

oiirinveintion eorisistsfm fa 'method of treating animalV fibres, eitheralone or mixed 'with ysolution-'ofa permangariatecompound, and eitherQwitnarifaqueous solution or Suspension of a nitro'geri-'cliloro'compound as hereinb'efore defined,

onwitha dilute Vaqueoussolution or suspension .of` an alkali nietalrroralkaline earth lm'etal hypochlorite for ulhypobromite. The solutions are@Q5 I luv' below. The oxidising agent has the effect of making theanimal fibres more susceptible to attack by the halogen-containingagent, with which they react to give materials having a high degree ofunshrinkability.

Our invention further comprises treating the materials with a diluteaqueous solution of a.

permanganate compound mixed with a dilute aqueous solution of an alkalimetal or alkaline earth metal hypochlorite or hypobromite at a regulatedpH Value.

Our invention further comprises a `process in which the materials arefirst treated in a dilute aqueous solution of a permanganate compound(e. g., an alkali metal permanganate) at a pH of approximately toapproximately 10, and at a temperature not exceeding 60 C., andsubsequently treated in a dilute aqueous solution or suspension of anitrogen-chloro compound of the type such as nitrogen trichloride,monochloramine, p-toluene-sulphonchloramide, etc., at a pH ofapproximately 1 to approximately 3.

Our invention further comprises a process in which the materials aretreated in a dilute aquecus solution of a permanganate compound (e. g.,an'alkali metal permanganate) at a pH of approximately 5 toapproximately 10V and at a temperature not exceeding '60 C. andsubsequently treated in an alkaline solution of `an alkali metal oralkaline earth metal hypochlorite or hypobromite, with or without theaddition of metallic salts such as magnesium sulphate, calcium chloride,calcium acetate, barium chloride, barium acetate and/ or zinc sulphateat a pH of approximately 7.5 to approximately 11.

Our invention further comprises treating the materials with a liquorwhich is alkaline and contains a dilute aqueous solution of an alkalimetal or alkaline earth metal hypochlorite or hypobromite, together witha permanganate compound (e. g., an alkali metal permanganate) at a pH,of approximately '7.5 to approximately 11.

The oxidising agent has theeffect of making the animal fibres moresusceptible to attack by the halogen-containing, agent, with vwhich theyreact to give materials having ahigh degree of unshrinkability. In allcases, only a relatively small concentration of permanganate, e. g., 1to 2% on the weight of the textile material, is required, and whilst foreconomic reasons one would employ the lowest concentration which givesthe desired; results, we have found that higher concentrations such as 5or 6% have no deleterious effects.

The treatment with permanganate may be carried 'out in the cold or atvaried temperatures, e. g., to 60 C. The treatment with thehalogencontaining agent may be carried on until exhaustion of thehalogen is obtained, and it is preferably followed by an antichlortreatment.

The solutions used are preferably adjusted to pH values ranging from5 to6 for the oxidising pretreatment, from 1,to 2 for the nitrogen-chlorosolution, and from 8to 10 for the hypohalite solution.

It is advantageous to employ the permanganate hypohalite method, withthe two reagents combined in one bath, since the mixture gives a stablesolution which will react in alkaline solution very slowly with wool orother animal fibre either inthe scoured state, or as received directlyfrom lthe spinning or knitting machine, to giveresistance to shrinkage.0The rate of this reaction is controlled,by lthe initialv pH of thebath, so that where it'fis advisable to give extremely slow treatmentsuch as with loose wool, or yarn in package form, it is possible bytaking an initial pH of 10.0 to obtain an even rate of oxidation takingupwards of one hour for exhaustion of the bath. But where goodsA arevigorously circulated such as in the treatment of Vhose or garments in arotary or paddle machine,

results which are still even are more rapidly obtained by lowering theinitial pH of the bath to approximately pH 7.5, when a regular rate ofexhaustion taking upwards of 30 minutes is obtained.

It is found that an addition of a metallic salt to the oxidising bathaids the reaction, without appreciably affecting the rate of exhaustionat a given pH, and in particular magnesium sulphate, calcium chloride,barium chloride, and

'Zinc sulphate, are useful for this purpose since,

either alone or in admixture, they also offer a ,simple method of pHcontrol. As the action proceeds, the pH of the bath usually falls alittle owing to the inefficient buffering of the metallic salts, but itis always advisable to maintain alkaline conditions throughout whenemploying the single bath as above. In all cases where the wool isintended for light shades or for White, it is necessary subsequently toremove the stainingA due to the permanganate by meansof the usualclearingntreatment, as with bisulphite or sulphurousacid. Animal fibresso processed are found to be appreciably bleached. .By slightlyincreasing the permanganate above the amount necessary to induce Y,unshrinkability in this alkaline treatment,Y it is possible to produce anexcellent bleach simultaneously with a high degree o f unshrinkability.

Resistance to shrinkage is alsov induced by rst subjecting the animallibres to treatment with a dilute aqueous solution of alkalinehypohalite particularly in the presence of the above metallic salts, andafter exhaustion ofthe bath to give the additional oxidationwith'permanganate, maintaining alkaline conditions throughout.

p The term alkali hypohalite as used herein is intended to designatealkali metal and alkaline earth metal hypochlorites and hypobromites.

The advantages of the processes of the present invention in comparisonwith the usual acid hypochloritechlorinating processes-are:

1. The animal fibres. are subjected to` an evenanti-shrink-treatment,which is readily controlled, and shows low; lossof proteinmatter.

2. The treatedA wool develops an improved soft handle and lustre, andretains its loftiness and resiliency even onv repeated washing.

3. A bleaching treatment; may be. given Vsimultaneously with theVanti-'shrinkprocess.

4. The processhas less effect on the colours of dyed wool.

5. The treated'woolisfmore. uniform; and subsequent dyeingv processesarefacilitated.:

6. The process can be carried-out in almost any type of machine, i., e.,wood.stainless steel, etc.

The following speciic examples are illustrative of the mannen in whichvthe treatment may be carried intov eifect. Y Y Y Eazmple1`-v-100 partsbyweight of, wool are treated-for 1 hour at 40 C. With a solutionof 2.5parts potassium permanganate in 2500 parts of water, correctedto pH 5.0.s

After giving one coldrinsegth'e wool is transferred to a solution ofmonochloramin'e prepared as follows: 3 parts of chlorine as sodiumhypochlorite ing2500Y parts of water,Vv to whichmixture is added 3 partsof ammoniumwchloride', followed niUU , and milling) by sniciex'ithydrochloric 'acid to bringtnefpH .to 1.5. After 20 minutesvcirculationin this liquor, Vthe wool is cleared ofqdiscolouration dueVtothe in tljiejhank are treated with Zuparts of potassium permanganateAin 2500 parts Aof water previously corrected to nH .Wiihvsulphuricacid!V After .eX-

.hausi'en 9i, thebaih. the wool, isgiven one rinse end theulsteepedin aiallure-Solution 0i Sodium sesquicarbonate until definitely alkaline. Itis `then entered into. a Cold Sciution containing 3 GROSS REFERENCEpartsof chlorine as sodium' hypochlorite to which Y ,has been; afi iel-` 10 parte ,oi calcium, ,chloride Vafter nroessineuniil .Completeexhaustion. f the chlorineisv obtained, anti-Chlor treatment withbisulpiiite and acid is given,-

ilt'pvample,3T-1070 partspfrall wool army half hose are treated in thegrease (orafter scouring with 2,500 parts of water containing:

Y Parts Potassium permanganate 2 Chlorine as sodium hypochlorite 4Calcium chloride 7 Zinc sulphate 3 Sulphonated fatty alcohol or suitablewetting agent 1/2 This oxidising mixture gives a pH of 8.2, and

the cold treatment in a paddle or rotary machine is continued untilcomplete exhaustion is obtained.` Acidied bisulphite solution is then'addedto the samefbath to remove the discolouration `due to thepermanganate.

Y Example 4 100 parts of 2'4/2 wool yarn in cheese form are treated-inthe grease with 2500 parts of water containing ll/z parts potassiumpermanganate, 21/2 parts of chlorine as sodium hypochlorite, 10 partscalcium chloride and 1/2 part sulphonatedfatty alcohol. This mixture'gives `a pH of approximately 11, and the cold treatment is continued ina pressure dyeing machine until exhaustion of the bath is obtained.

Acidied bisulphite solution is then added and processing continued untilthe discolouration of the permanganate is removed.

Example 5.--100 parts of 12/4 Botany yarn in the grease are treated with2500 parts of Water containing:

Parts Chlorine as sodium hypochlorite 3 Calcium chloride 10 Sulphonatedfatty alcohol or suitable wetting agent 1/2 Parts Potassium permanganate2 Bromine as sodium hypobromite 3 Calcium chloride 10 Sulphonated fattyalcohol or suitable wetting agent 1A? The solution of sodium hypobromiteis con- Example 7'.- 100parts ofsooured 'l2/l Botany is treaiedwithZParis 0f perinaiieaneie in 2500 parts of water.corrected to pI-I 5 withsulphuri'c acid, forni hour in the cold. `It is then lifted andre-entered intoV a fresh bath containing 5 parts of sodiump-toluene-sulphonchloramide in 2500 parts of Water, corrected to pHZwithhydrochloric aci/d.l This treatment is continued in the cold fo-r about20minutos, or until complete exhaustion of the chlramine, after whichthe discolouration due4 to the permanganate is rrnoved by addition Vofbisulphite to the same lqup'- l The expression fto reduethenaturaltendency to shrinkwhen 4 washed inaqueous liquorsf. and similarexpressions used hereinare intended to designate either neutral Yoralkaline liquors which have a natural tendency to cause shrinkage inwoot Y vWhat-we claim is: K

1. A method of treating fabrics and other textile materials consistingat last'in part .of Wool.

to reduce the natural tendency to shrink when washed in aqueous liquors,comprising treating such materials with a dilute aqueous solution of analkali metal permanganate at a pI-I o f not less than about 5 and with adilute aqueous solution containing a substance selected from the groupconsisting of alkalihypohalite at a pH of at least 7f.5 and anitrogen-chloro compound in which the chlorine atom is directly attachedto the nitrogen 4atom and in whichthe chlorine is present as availablechlorinehaving a pI-I of about 1 to 3.

t 12. A method of treating fabrics and other textile materialsconsisting at least in part of wool, to reduce the natural tendency toshrink when washed in aqueous liquors, comprising treating the textilematerials with a dilute aqueous solution of an alkali metal permanganatemixed with a dilute aqueous solution containing an alkali hypohalite ata pH of approximately 7.5 to approximately 11.

3. A method of treating fabrics and other textile materials consistingat least in part of wool, to reduce the natural tendency to shrink whenwashed in aqueous liquors, comprising treating the textile materialswith a dilute aqueous solution of an alkali metal permanganate at a pI-Iof 5 to 10 and at a temperature not exceeding 60 C'., and subsequentlytreating them with a dilute aqueous solution containing anitrogen-chloro compound at a pH of 1 to 3.

4. A method of treating fabrics and other textile materials consistingat least in part of Wool, to reduce the natural tendency to shrink whenWashed in aqueous liquors, comprising treating the textile materialswith a dilute aqueous solution of an alkali metal permanganate at a pHof lrlill nuo 7 the textile materials with a dilute aqueous solution ofan alkali metal permanganate at a pH of not less than about and withavdilute aqueous solution containing an alkali hypohalite at a pH of atleast 7.5 and a metal salt selected from the group consisting ofmagnesium sulphate, calcium chloride, calcium acetate, barium chloride,barium acetate, and zinc sulphate.

6. A method of treating fabrics and other textile materials consistingat least in part of wool, to reduce the natural tendency to shrink whenwashed in aqueous liquors, comprising treating the textile materialswith a dilute aqueous solution containing an alkali hypohaliteat a pH of7.5 to approximately 11 and subsequently treating them with a diluteaqueous solution of an alkali metal permanganate at a pH over 7.

7. A method as claimed in claim 1, in which the permanganate compound ispotassium permanganate.

8. Textile materials containing Wool, which have had the naturaltendency to shrink when washed in aqueous liquors reduced by treatmentwith a dilute aqueous solution of an alkali metal permanganate at a, pHof not less than about 5 and with a dilute aqueous solution containing asubstance selected from the group consisting of alkali hypochlorite at apH of at least 7.5 and a nitrogen-chloro compound in which the chlorineatom is directly attached to the nitrogen atom and in which the chlorineis present as available chlorine having a, pH of about 1 to 3.

9. A method as claimed in claim 1, in which the concentration of analkali metal permanganate is less than 6% on the weight of the textilematerial.

10. A liquor for treating textile materials containing Wool in order toreduce the natural tendency to shrink when Washed in aqueous liquors,said liquor containing an alkali metal permanganate, an alkalihypohalite and a metal salt selected from the group consisting ofmagnesium sulphate, calcium chloride, calcium acetate, barium chloride,barium acetate, zinc sulphate having a pH of approximately 7.5 toapproximately 11. y

11. A method of treating fabrics and other textile materials consistingat least in part of Wool, to reduce the natural tendency to shrink whenwashed in aqueous liquors, comprising treating the textile materialswith a single bath containing a dilute aqueous solution of an alkalimetal permanganate and a dilute aqueous solution of an alkali metalhypochlorite at a pH of approximately 7.5 to approximately 11 until apermanent resistance to shrinkage against alkaline liquors occurs.

12. A method of treating fabrics and other textile materials consistingat least in part of wool, to reduce the natural tendency to shrink whenwashed in aqueous liquors, comprising treating the textile materialswith a single bath containing a dilute aqueous solution of an alkalimetal permanganate and a dilute aqueous solution of an alkali metalhypochlorite at a pH of approximately 7.5 to approximately 11 until apermanent resistance to shrinkage against alkaline liquors occurs, andthereafter removing any discoloration due to the permanganate.

FRANCIS MALCOLM .STEVENSONZ JOHN LEONARD RAYNES.

REFERENCES CITED The following references are of record in the le ofthis patent:

I UNITED STATES PATENTS Number Name Date 1,781,415 Smith Nov. 11, 1930145,816 Rickards Dec. 23, 1873 809,869 Wakeeld Jan. 9, 1906 644,670Green Mar. 6, 1900 FOREIGN PATENTS Number Country Date 5,612 GreatBritain 1907 473,869 Germany Mar. 22, 1929 3,669 Great Britain Mar. 6,1900 569,730 Great Britain June 20, 1945

